A protocol is presented for the rapid (28 days) induction of microtubers on micropropagated layered potato plantlets of 'Kennebec', 'Russet Burbank' and 'Superior' in medium devoid of growth regulators. With this method the addition of coumarin, 6-(2-chloroethyl)-trimethylammonium chloride and 6-benzylamino-purine to the microtuberization medium either had no effect or significantly reduced microtuber weight per plantlet. Increasing the incubation period from 28 to 56 days significantly increased the weight of microtubers per plantlet and the proportion of microtubers heavier than 1 gram. Increasing the volume of microtuberization medium from 50 to 100 ml significantly increased the number of microtubers per plantlet. Microtuber dormancy periods were cultivar-specific and microtubers $ le$250 mg had longer dormancy periods as compared to microtubers $>$250 mg. A positive correlation was established between endogenous abscisic acid levels and microtuber dormancy periods. Microtubers $ le$250 mg had lower specific gravity, fewer eyes and produce fewer sprouts than microtubers $>$250 mg. Microtuber-derived plants were generally single-stemmed. Severe physiological ageing treatment ($>$2500 degree-days) had no effect on microtuber sprout development, stem number, tuber number and only minimally influenced tuber weight of microtuber-derived plants. Decreasing field in-row planting density from 30 to 10 cm reduced tuber weights and numbers per plant but increased them on a per hectare basis. Economic analysis indicated that optimum planting density varied depending on plantlet cost. The optimum planting density was 10 cm if the cost of the plantlet was $0.10 or less, 20 if plantlet cost were from $0.10 and $0.20 and 30 cm for plantlet cost greater than $0.20. A potato seed tuber certification program adapted to the needs and constraints of Egypt is presented.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.41512 |
| Date | January 1993 |
| Creators | Leclerc, Yves |
| Contributors | Donnelly, D. J. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Plant Science.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001382928, proquestno: NN91659, Theses scanned by UMI/ProQuest. |
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